A parallel link robot has characteristics of, for example, very lightweight configuration of movable sections serving as fingers, relatively low manufacture cost, and elimination of a need to move motors themselves due to concentrated arrangement of driving motors on a base. Therefore, in recent years, the parallel link robot attracts attention as an industrial robot.
A parallel link robot described in Patent Document 1 is generally called hexa-type parallel link robot. It includes, for example, a total of three sets of two arms and the three sets of arms are connected to a periphery of a movable plate via universal joints (e.g., see paragraph [0015] of Patent Document 1).
Such a hexa-type parallel link structure is characterized in that it is simple, can be easily designed, and has a wide range of translational motion. However, with this structure, a range of rotational motion of the movable plate is small and about ±30° is the limit.
A parallel link robot described in Patent Document 2 is capable of performing a translational motion having three degrees of freedom due to parallel links. Further, the parallel link robot includes a drive mechanism that rotates members called posture-changing mechanism unit around three axes with respect to movable members serving as fingers. This drive mechanism transmits driving force for motors, which are provided in an upper portion, to the posture-changing mechanism unit via driving shafts (54-1, 54-2, 54-3).
Patent Document 1: Japanese Patent Application Laid-open No. 2013-059852
Patent Document 2: Japanese Patent No. 4659098